Downhole Pressuremeter Tool for Static Elastic Modulus
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Solution Overview
Problem
Conventional methods for determining the static elastic modulus of subterranean formations are time-consuming and require laboratory tests on core samples, whereas in situ methods are either destructive or lack efficiency in characterizing unconsolidated formations.
Innovation Solution
A downhole tool system that performs pressuremeter tests using inflatable packers to induce radial deformation and apply load-unload cycles, combined with cavity expansion theory for real-time derivation of static elastic properties, allowing for non-destructive and efficient characterization of both consolidated and unconsolidated rock formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laboratory tests on core samples are used to determine static elastic modulus, then measurement precision is improved, but loss of time increases significantly
Solution Approach 1:
The patent replaces conventional laboratory mechanical testing of core samples with an in-situ pressuremeter testing system that uses inflatable packers to apply radial stress directly in the wellbore. The system substitutes physical core extraction and lab analysis with downhole mechanical testing, achieving rapid static elastic modulus determination without removing formation samples.
Solution Approach 2:
The patent introduces a pressuremeter tool with inflatable packers as an intermediary device between the formation and measurement system. The packers inflate against the wellbore wall to apply controlled radial stress, serving as a mediator that enables direct in-situ measurement of formation elastic properties without requiring core samples or complex laboratory setups.
2Productivity
If in situ pressuremeter tests are performed using inflatable packers, then productivity is improved through rapid data acquisition, but device complexity increases
Solution Approach 1:
The pressuremeter tool integrates multiple functions into a single downhole device: it performs formation testing, measures pressure-volume relationships, conducts load-unload cycles, and determines static elastic modulus. The inflatable packers serve multiple purposes by sealing the wellbore and applying controlled radial stress, eliminating the need for separate core sampling and laboratory testing equipment.
Solution Approach 2:
The system utilizes changes in pressure, volume, and stress parameters during packer inflation and deflation cycles to derive formation elastic properties. By monitoring pressure-volume relationships and analyzing the slopes of inflation and deflation curves, the system transforms mechanical test data into quantitative static elastic modulus values, enabling rapid productivity improvement.
3Reliability
If load-unload cycles are applied during packer inflation, then reliability of elastic property measurement is improved, but duration of action increases
Solution Approach 1:
The patent employs periodic load-unload cycles during packer inflation, where the packer is inflated to a target pressure, held, deflated, and then re-inflated in repeated cycles. This periodic testing approach allows the formation to respond elastically to stress changes, and by analyzing the pressure-volume relationships during these cycles, reliable static elastic modulus values are obtained while maintaining efficient testing duration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid and accurate determination of static elastic properties in situ, reducing the time required for data acquisition from months to a few hours, and provides comprehensive geomechanical parameters for improved formation evaluation and optimization of oil and gas extraction.
Implementation Method 1
A downhole tool system that performs pressuremeter tests using inflatable packers to induce radial deformation
Data Source
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AI summary
A method that includes lowering a formation testing tool into a wellbore intersecting a subterranean formation. The formation testing tool comprises an expandable member. The method also includes performing a pressuremeter test (PMT) by expanding the expandable member.